• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.494-497
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• 2003

A rotating device driven by an Inchworm motor was designed and fabricated to be used as an angie standard system. 1. PZT was adopted as a driving source, while the movement of PZT was guided by the leaf spring employing the elastic transformation of metals. 2. The device could rotate in a 360-degree arc. continuously Performance test of the device showed about 0.02 sec. of the minimum revolution angle and 1/15 rpm of the maimum revolution speed. 3. To improve its performance requires further studies on realizing a shifting device with faster response time, on increasing the output current (capacity) of the power amplifier used to drive PZT, on the dynamic motion of clamping. and on determining the optimum clamping condition

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.94-97
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• 2007

The desin and implementation of a CMOS analog integrated circuit that provides dual-mode modulations, PWM for active clamp reset converter and PFM for LLC resonant converter, is described. The proposed controller is capable of implementing programmable soft start and current-mode control with compensating ramp for PWM and frequency shifting soft start for PFM. Also it provides delay time for both modes. PWM mode is implemented by active clamp reset converter and PFM mode is implemented by LLC resonant convereter, respectively. The chip is fabricated using the 0.6um high voltage CMOS process.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.974-979
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• 2007

From '1994 Gwacheon accident of the Electric Multiple Unit(EMU)' till '2004 Seoul subway 2 lines Guui station accident', the accident is increasing at day and the service demand of the citizen is coming to be various. But it does not deal with technical or operation side demands. There is a possibility of saying that the accident of the EMU or deficit operation is caused by the RCM. The EMU where the efficiency is good though does the time passes and it becomes old anger and does not display that efficiency not only the cause of formation accident does becomes. The breakdown about under occurring before getting up an accident, appropriately shifting the parts is to a maintenance very the pending question fact which is important is a possibility of doing. From there is by an EMU, RCM in reliability base grudge is a tool of confirms an improvement point and the place where it judges. From the research which it sees will present about technical development plan of RCM.

• Nuclear Engineering and Technology
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• v.41 no.3
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• pp.237-246
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• 2009

Digitalization of not only non-safety but also safety-grade I &C systems with full computerized Main Control Room (MCR) is the recent trend of I&C systems of nuclear power plants (NPP) around the world, while plant maintenance has been shifting from traditional time based maintenance to condition based maintenance. In order to cope with the new trend of operation and maintenance in NPP, a concept of online distributed diagnostic system for both plant operation and maintenance has been proposed in order to further improve both the plant efficiency and the work environment of plant operation staff members by organizational learning. In this respect, the research subjects of human machine interface (HMI) for the online distributed diagnostic system are also discussed for supporting the plant personnel at both MCR and local working places in the plant by the application of advanced ICT (Information and Communication Technologies).

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.9 s.114
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• pp.958-963
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• 2006

The motion of a system composed of a plate, constant springs and varying dampers is considered when the system is subject to harmonic force. Letting the frequencies of harmonic force and damper variation $f_1\;and\;f_2$, respectively, the displacement at the center of the plate has the strongest component at frequency $f_1$. The angular displacement of the plate has strong components at $f_1-f_2$ and the natural frequency of the rotational mode of the system. If these two frequencies coincide, the plate oscillates with almost single frequency and a large amplitude. These results can be applied to development of a moment shaker with low frequencies.

• Journal of KSNVE
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• v.9 no.3
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• pp.509-516
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• 1999

The ESPI (Electronic Speckle Pattern Interferometry) algorithm has been simulated to calculate vibrational modes of a thin right-angled STS304 plate. The phase transformation of the reference wave of the ESPI is carried out only one time during vibration in order to clarify ESPI speckle patterns. Two dimensional vibrational modes are calculated from one ESPI pattern before vibration onset and two ESPI patterns during vibrations but with and without the phase transformation. The ESPI harmonic results are compared with those derived from the finite element method (FEM), and they agree very well. Additionally a phase unwrapping algorithm has been newly developed to derive a displacement map from an ESPI phase map.

• Journal of Industrial Technology
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• v.35
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• pp.55-58
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• 2015

Natural shifting of rivers has been disturbed by anthropological activities. Urbanization in Kathmandu has been encroached the natural floodplain of Bagmati and currently channeled by training walls. The study compares the change in shape of Dhobikhola, a small tributary using 1966 and 2014 satellite images. It has been found that the original shape is heavily changed over time at the beginning and end section of river under study. The river width is now fixed by training walls and roads along the banks. Using multiple data sets like satellite images and GIS analysis, these shifts can be easily detected to plan for management and restoration of physical and ecological behaviors of rivers.

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.499-507
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• 2000

Smooth shift is one of the key issues in automatic power transmission control systems. However, the torque sensors are too expensive to be used in shift controllers on production vehicles. In order to provide a basic strategy for smooth shifting by using RPM sensors only and in order to accomplish the shift within a designated time, this paper studies detailed characteristics of the smooth shift for clutch-to-clutch shift mechanism. A desired trajectory of slip speed is proposed for smooth acceleration shift defined in this paper. Also the clutch torque needed to achieve this trajectory is derived, and it may be used as a open loop shift control law.

• Journal of Power Electronics
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• v.8 no.4
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• pp.317-324
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• 2008

This paper proposes a Multiband Shunt Hybrid Active Filter (SHAF) with sensorless control. A plant is modeled in the discrete- time domain and a controller is designed using the Pole shifting law in the polynomial domain. This control approach is very useful for filtering the load harmonics with reduced sensor counts where a low cost solution like SHAF is required. Multiple Synchronous Reference Frames (MSRF) and low pass filters are used to measure the $5^{th}$ and $7^{th}$ harmonic components separately from the load and filter currents. Individual current controllers are designed for the $5^{th}$ and $7^{th}$ harmonic currents. Control is realized in the stationary, three-phase (abc) reference frame. Performance of the controller is validated through simulation, using realistic plant and controller models, as well as experimentally on a full-scale distribution system.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.2
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• pp.7-20
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• 2007

TCU is a shift controller far automatic transmission of which major functions are to determine the shift point and manage the shifting process based on the various input signals. As the recent digital control technologies advance, it plays a key-role to improve a transmission performance and its algorithm becomes more complicated. This paper describes the development of transmission simulator fur wheel loader that enables a TCU for normal stand-alone operation by the real-time emulation of TCU interface signals. It can be utilized for the analysis of shift control algorithm implemented in a commercial TCU as well as for the development of brand new TCU.